脉冲激光沉积法（PLD）制备非晶态BZN薄膜的研究

关 键 词：BZN；PLD；非晶态；
 ABSTRACT
Bi2O3-ZnO-Nb2O5 (BZN) pyrochlore ceramics have been developed for low firing temperature capacitor and microwave dielectric device, because they posses a middle dielectric constant, low dielectric loss. In recent years large dielectric tunability of the BZN films was found and reported, which suggested that BZN had potential application for integrated microwave components. The investagation of BZN system, especially BZN films, has been drawing attention to the researchers from academic and industrials.

In this paper, amorphous BZN thin films were successfully prepared by pulsed laser deposition (PLD) on the Pt electrode coated Si substrates. The oxygen pressure and annealing temperature of the Bi1.5ZnNb1.5O7 films were investigated. Different oxygen pressure and different annealing temperature were experimented to show how they influence the dielectric properties and film structures. BZN thin films were all amorphous phase below 200 ℃ from the SEM and XRD results. With the increase of oxygen pressure, the thickness of Bi1.5ZnNb1.5O7 films increase accordingly, the morphology of BZN films surface becomes rougher and the less compact. Dielectric constant show that films annealed at 150℃ own the best dielectric property. Bi1.5ZnNb1.5O7  Films deposited at 1 Pa, annealed at 150℃ has the dielectric constant of 60.1, loss tangent of 0.0083 at the frequency of 10kHz, leakage current density of the Bi1.5ZnNb1.5O7 film is about 1×10-7A/cm2 at DC bias electrical field 0.3MV/cm.

KEY WORDS: BZN; PLD; Amorphous phase; Dielectric

目  录
第1章 绪 论 1
1.1 电介质材料 1
1.2 微波介质材料 1
1.3 BZN焦绿石 2
1.3.1 焦绿石结构 2
1.3.2 BZN陶瓷的相结构和微波性质 2
1.3.3 BZN薄膜的研究现状 3
1.3.4 BZN薄膜介电可调机理 4
1.4 本论文研究的选题依据和任务 4
第2章 BZN陶瓷靶材的制备与表征 6
2.1 BZN陶瓷靶材的制备工艺 6
2.2 BZN陶瓷样品的XRD分析 8
2.3 陶瓷样品SEM分析 9
2.4 陶瓷样品介电性能表征 10
2.5 BZN陶瓷靶材的制备 12
2.6 本章小结 14
第3章 Bi1.5ZnNb1.5O7薄膜的制备 15
3.1 PLD工艺简介 15
3.2 PLD制备BZN薄膜的工艺 18
3.2.1 沉积参数 18
3.2.2 制备操作流程 18
3.2.3 薄膜制备中氧压的控制 18
3.3 后退火处理 19
3.4 Bi1.5ZnNb1.5O7薄膜的结构和形貌 20
3.4.1 Bi1.5ZnNb1.5O7薄膜XRD分析 20
3.4.2 Bi1.5ZnNb1.5O7薄膜SEM分析 21
3.4.3 Bi1.5ZnNb1.5O7薄膜AFM分析 22
3.4.4 Bi1.5ZnNb1.5O7薄膜厚度分析 24
3.5 本章小结 25
第4章 Bi1.5ZnNb1.5O7薄膜的电学性能 26
4.1 Bi1.5ZnNb1.5O7薄膜介电频谱分析 26
4.2 Bi1.5ZnNb1.5O7薄膜漏电流特性 29
4.3 影响薄膜电性能的因素 30
4.4薄膜性能的优化 31
4.5 本章小结 31
第5章 结论与展望 32
致  谢 33
参考文献 35